Polyazo dyestuffs of the pyrazolone series and a process of making same



Patented Aug. 1, 1950 1'3 UNITED STATES PATENT "OFFICE 2,517,312 rPOLYAZO DYESTUFFS oF THE PYRAZOLONE SERIES AND A PROCESS OF MAKING SAMEA Peter Hindermann, Basel, Switzerland, assignor to J. R. Geigy A. G.,Basel, Switzerland, a Swiss firm t l No Drawing. Application December31,1946, SeriallsNo. 719,636. In Switzerland December 27, 19

Section 1, Public Law 690, August 8, 1946 Patentexpires December 27,1965 8 Claims. (Cl. 260+159) l I have found that valuable metallisabletetraate product resulting from a tetrazonium comkisazo dyestuffs areobtained, if tetrazo compound of an aromatic diamine and of a molarpounds of a simple or combined polynuclear aroquantity of the monoazodyestuii of the above matic diamine which can still further besubstigeneral Formula I to react with a molar quantity tuted are coupledwith two monoazo dyestulfs 5 of an aminopyrazolone of the above generalForeither of the same or different constitution and mulaII in order toproduce the aminotrisazo dyeof the general formula stuiflwhich is thenlinked by means of phosgene H038 N=NOH--GO x o o-on,

' N--Z-NH- NH-Z-N 2N l l l I N02 Y V wherein or thiophosgene accordingto known methods X means oxygen or a sulfuratom, I

Each Y represents a methyl, ethyl or phenyl ling 1 mole of I-diazo-6nitro-2-hydroxynaphgroup and H thalene-fl-sulfonic acid with 1 mole ofamino- Each Z stands for a member of the group conpyrazolone of theabove general Formula II.

sisting of radicals of the benzene series bound Simple and combinedaromatic diamines suitwith the 'aminomonoazo dyestuff made by coup-' in1:4-position and of radicals of the diphenyl able for the presentmethodare for instance the series bound in MP-position. k ll-diamino compoundsof diphenyl, of diphenyl The coupling of the, said tetrazo compoundswith one mole of the above defined monoazo dyestuffs for producing theso-called intermediate product takes readily place in a slightly acid,neutral or slightly alkaline medium, whereas the subsequent couplingwith a second mole of the monoazo dyestuff of the above general FormulaI can also be carried out in a slightly acid, neutral or slightlyalkaline medium, whereby the tetrakisazo dyestufi is produced. V

The same metallisable tetrakisazo dyestuffs are also obtained by firstcombining the tetrazotised aromatic diamine with 1 mole of the monoazodyestufi of the above general Formula I, thus yielding the intermediateproduct, then coupling the latter with a molar quantity of adipyrazolone obtainable by condensation of 2 moles of an aminopyrazolonederivative of the general For- 40 diphenyl ketone, of diphenyl urea, ofstilbene,

acid groups and the like.

powders. When subjected 'to 'a treatment with metal-yielding agentseither in, substance or on methane, of diphenyl sulfide, of diphenyl sulfoxide, of diphenyl sul'fone, of diphenyl amine,;of

moreover the 3-,aminoor 4-amino-benzoy1 de rivatives of 1:3- andlzl-diaminobenzene or of the above enumerated diamino compounds or ofother dia mino compounds. The aromaticrings 30 of the said diamines cancarry .still further substituents suc h, as for example alkyl, halogen,M hydroxyl, ,alko y. acylamlno, carboxy, sulfonic;

The new dyestufis form red-brown to dark thefibre according tousualmethods, the new dyestufis can be transformed into metal com? plexcompounds. The copper complex com- I: pounds are particularly valuablebecause of their excellent light-fastness. The coppering can be mumHICFCO effected, as is known, for instance with copper l r sulfate in aneutral or slightly acetic acid bath --zNHl a V or also inthe presenceof alkali tartrates in a =N slightly alkaline bath. In this wayorange-red II or red dyeings will be produced, which are fast. f whereinY and Z have the above meaning, with to light andalkalis and which oftensurprisingly I phosgene or thiophosgene or carbon disulfide repossessalso good fastness properties in the moist spectively'and finallyinteracting .the resultant state. trisazo dyestufi with a molar quantityof l-dia'zo- Because of their easy availability and due to6-nitro-2-hydroxynaphthalene-4-sulfonic acid. their improved drawingpower onto cellulosic A further method for making the new tetrafibresthe tetrakisazo dyestufis of l-(4-amino kisazo dyestuffs of my presentinvention conphenyl)-3-methyl-5 pyrazolone-urea are pre- Q sists inthataminoazo dyestufis are treated with rerred. Those dyestuffs, whosearomatic diamine phosgene, for instance by causing the intermedimiddlecomponents still contain metallisable state, if the dyeings producedwith said dyestuffs on cellulosic fibres are after-treated with coppersalts.

The following examples, Without being limitative, Will illustrate thepresent invention. The parts are by weight, unless otherwise stated.

Example 1 22.7 parts of l-(4-aminobenz oylan 1ino) -4- aminobenzene aretetrazotised in a hydrochloric acid solution with 13.8 parts of sodiumnitrite and the tetrazo compound made slightly acid to Congo combined ina bic'arbonatic medium with 69.3 parts of the monoazo dyestuff obtainedby coupling 1-diaao-6-nitro-2-hydroxynaphthalene- 4-sulfonic acid on oneside with the urea of 1-(4-. aminophenyl)-3-methyl-5-pyrazolone, wherebythere results the intermediate product. After completion of the coupling'72.? parts of the monoazo dyestufi made by coupling l-diazo-G-nitro-2-hydroxynaphthalene-4-sulfonic acid on one side with urea of1-(4-amino-2'-methylphenyl) 3-methyl-5-pyrazolone are added thereto.After stirring for several hours at room temperature the coupling iscomplete. Then the dyestuff is precipitated by addition of sodiumchloride, filtered and dried. It constitutes a dark powder soluble inwater with a red coloration and in concentrated sulfuric acid with anorange coloration. It dyes cellulosic fibres in brown-red shades whichare changed to red by an after-treatment with copper salts, theresulting red shades being distinguished by good fastness properties tolight and in the moist state.

The urea of 1-(4-amino-2'-methylphenyl)-3- methyl--pyrazolone can bemade by introducing phosgene into a solution of' 40.6 parts of the saidamino-pyrazolone in 500 parts of water in the presence of an excess ofsodium carbonate at room temperature, until no more free amino groupscan be traced.

The urea of l-(4-aminophenyl)-3-methyl-5-. pyrazolone can be producedaccording to a quite similar method by causing 37.8 parts of 1-(4-aminophenyl) -3-methyl-5--pyrazolone, instead of razolone, to react withphosgene.

Example 2 28 parts of 4:4-dihydr oxy-3 3'-diaminophenylsulfone aretetrazotised with. 13.8 parts of sodium nitrite in a hydrochloric acidsolution. The tetrazo compound treated with sodium carbonate, until theCongo acid reaction has disappeared, is combined in a soda-alkalinemedium with 139.8 parts of the monoazo dyestuff produced from nitrateddiazo compound of I-amino-Z-hydroxynaphthalenel-sulfonic acid and ureaof 1-(4- aminophenyl) -3-methyl-5-pyrazolon e. Then the mixture isstirred for several hours at room temperature. After completed couplingthe dyestufE is precipitated with sodium chloride, filtered and dried,It constitutes a dark powder which dissolves in water with a browncoloration and in concentrated sulfuric acid with an orange, coloration;the new dyestuff dyes cellulosic fibres in brownshades which, by anafter-treatment with p er salts. a conve t d into orange-red shad s.

of very good light-fastness and fastness in the moist state.

Dyestufis having similar properties will be obtained, when using,instead of the 4:4-dihydroxy- 3:3-diaminodiphenylsulfone, acorresponding quantity of 4 4' -dihydroxy-3 3-diaminodiphenylketone or 44' -diamino-3 :3 -dihydroxydiphenyl.

Example 3 40.4 parts of urea of 1-(4'-aminophenyl)-3-methyl-5-pyrazolone are combined in a sodaalkaline solution with theintermediate product made from the tetrazonium compound of 18.4 parts of4:4-diaminodiphenyl and 69.9 parts of the monoazo dyestuff obtained from1-diazo-6- nitro--2-hydroxynaphthalene-4-'sulfonic acid and the urea of1-(4-aminophenyl) -3-methyl-5-pyrazolone, thus yielding the one-sidedcoupling product. As soon as no more traces of the diazo intermediateproduct can be detected, the mixture is coupled with 29.5 parts ofl-diazo-fi-nitro- 2-hydroxynaphthalene-4-sulfonic acid in the samesoda-alkaline solution as that used above. The new tetrakisazo dyestufiis precipitated with sodium chloride, isolated and dried. It forms adark powder which is soluble in water with a red-brown coloration and inconcentrated sulfuric acid with an orange coloration and which dyescellulosic fibres from av neutral dye-bath containing Glaubers salt inbrown-red shades. By an after-treatment with copper sulfate there resultred shades possessing excellentv fastness properties.

The same dyestuff can also be produced by combining the tetrazoniumcompound resulting from 18.4. parts of 4,:4'-diaminodiphenyl with 139.8parts of the monoazo dyestufi obtainable from1-diazo-6-nitro-2hydroxy-naphthalene-4- sulfonic acid and urea of1-(4-aminophenyl)-3- methyl-firazolone in a bicarbonatic medium.

Example 4 24.4 parts of 4:4K-diamino-3:3'-dimethoxydiphenyl aretetrazotised in a hydrochloric acid solution with 13.8 parts of sodiumnitrite. The tetrazo compound treated with sodium carbonate, until theCongo acid reaction'has been removed is combined in a litmus-neutralmedium with 139.8 parts of the monoazo deystufl' produced from,1-diazo-G-nitro-2-hydroxynaphtha,- lene-4-sulfonic acid and from theurea of l-(' aminophenyl) -'3 -meth l-5-pyrazolone. The mixture isstirred for some. hours at room temperature, whereupon the coupling iscomplete. The dyestufi is then precipitated with sodiumchloride,'filtered and dried. It forms a dark powder which dissolves inwater with a red-brown coloration and in concentrated sulfuric acid withan orange coloration. The new dyestufi dyes, cellulosic fibresinbrownish-red shades which, by an after-treatment with copper sulfate,are changed into red shades of good fastness properties to light and towater.

A dyestuff having a somewhat more blueish shade but otherwise the same"properties as the above described one, can be obtained whentetrazetizing in the manner disclosed: in the above example; 21.6 partsof 4;:4"-diamino-3:3.'-dihydroxydiphenyl, instead of 4 4'-diamino-3 :3'-dimethQXydiphenyl, then coupling the resulting intermediate productwith the monoazo dyestuff in a soda-alkaline medium and otherwiseproceeding. in exactly the same; manner as described above;

Example obtained from 1-diazo-6-nitro-2-hydroxynaphthalene-4-sulfonicacid and the urea of 1-(4'- aminophenyl) 3 methyl 5 pyrazolone. After itgenerated cellulose in brownish-red shades which,

some hours the coupling is complete and the dyes stuff isolated withsodium chloride,.filtered and dried. It constitutes a dark powder whichis soluble in water with a brown-red coloration and by anafter-treatment with copper salts, are changed to red shades of goodfastness properties to light and in the moist state.

The same dyestufi can also be obtained by interacting the abovedescribed intermediate product resulting from the tetrazo compound of,26.4 parts of benzidine monosulfonic'. acid and 76.8 parts of themonoazo dyestulf, produced iromf- 1 diazo 6 -nitro 2hydroi'zynaphthalene I- 4-3 sulfonic acid and from the urea of-1-(4"--amino 2'-chloropheny1) 3 methyl-5-pyrazolone, with 82.3 parts ofthe monoazo. dyestufi made from, 1 diazo 6 nitro 2 hydroxy naphthalenein concentrated sulfuric acid with an orange 4-sulfonic acid and fromthemes. of 1- atamino: coloration. From a neutral dye-bath containingphenyl) -3.-phenyl-5-pyrazolone, whereby the Glaubers salt cellulosicfibres will be dyed with tetrakisazo dyestufi is obtained. l. the saidnew dyestufi in brown-red shades which, The urea -of 1-(4'-amino;2'h1 1) .3; when after-treated with copper salts, areconmethyl-fi-pyrazolone i obtain d by introducing verted in o a red fgood fastness pr perties. phosgene into a solution of 44.7. partsof'the'said aminopyrazolone in 500 parts" of water .in the Example 6 rpresence of an excess of sodium carbonate at The tetrazomum compoundfrom 26.4 parts of room temperature, until n more free aminqbenzidinemonosulfonic acid is coupled in a slightly groups can betraced. aeetic acid Solution parts of the mOnO- When interacting partsof 1 (4';,amino;f azo dyestuff obtainable from 1-d azo-6-mtro-2- phenyl)5 1 t phos'gene. hydroxynaphthalene-4-sulfon1c acid and the urea twrresponding urea Obtained accqming t of 1-(4'-amino-2'-chlorophenyl)3-methyl-5- th same t pyrazolone. After some hours the formation of The1- 4' amin -2'-chlorophenyl).-3 methy1=.; the intermediate product iscomplete. Then a 5-pyraz01 is obtai v interacting 13 vparts n tr ls lu f25. par o of aceto acetic acid ethylesterwi-th 18.75 arts ph nyl)- -p y1S allowed tqfiow of 4-nitro-2-chloro-phenyl-hydrazine in boilingtherelnto, up n 10 Pa s Of 8001111111 blcaralcohol, whereby first the1-(4"-nitro-2.'-ch10ro-.- bonate in 200 parts of water are graduallyadded phenyl) ..3..mef,hy1 5..pyrazo1one is formed which: d p by d pAfter q p 0011D1 mg the new by reduction wtih iron is converted into theabove aminotrisazo dyestufl is isolated, again taken up said aminopymzolona l in 10 00 parts of water, made distinctly brilliantw ninteractingrothel-acyl acetic and alkaline by means of sodium carbonateand conubstituted p-nitrophenyl-hydrazines inequivadensed w t ph e e andwith the amlnpazo lent quantities, the corresponding 1-(4-nitrodyestufimade from 29.5 parts of 1-d1azo-6-n1tro- 40 phenyl) ..5-pyra,zo1one5 or..(4'-aminopheny1) -5: Z- Yd Y P M- acld and pyrazolones respectivelywillbe obtained which, Parts Of '-a y --pheny1 -Dyrazowith respect totheir properties, are very similar lone, until no more free ammo groupscan be to those of the above'described'1-(4" amino-2"- traced. Thetetrakisazo dyestufi thus formed ischlorophenyl)-3-methyl-5-pyrazolone.. 3 precipitated with sodiumchloride, isolated and The following table sets forth additionalexdried. It is a dark powder which dissolves in amples of dyestufisaccording to the pre's'entin; water with a brown-red coloration and incon vention, the process of preparation being essencentrated sulfuricacid with an orange color. tially analogous to the process described inthe The new dyestufi dyes cotton and fibres from repreceding examples. ly

\ Table Montoazg hdgestufi filo?1 ll-diafiol-fi- Mgiogzlcli gryestufil-diazol-lfi-ni- Salado of lithe l 89118 S 0- 0X 8 9118- $11 No gu i aciah d f figwing dipyrazo- Aromatic naming acid a d tollfi wi g dipyrazolone l z co i i ed 0% lone according to formula I cording toformula I eel ulosic fibres l"--- urea from l-(4-aminophenyl)-3-4:4-diaminodiphenylmethane urea from l-( i-aminophenyl)-3-, red.methyl-S-pyrazolone. methyI-5-pyrazolone.- e NF. 2 do4z4"-diagiinodiphenyl-uma-3z3disulfondo reddish-mange,

1 8 1 3 do 4z4 -diiiminodiphenyl-ur do i. red. 4- thioureafrom1-(4-aminophenyl)-3 4:4-diamino-dipheny1 thiourea from1-(4'-ami.nopheny1)-3 Do. methyl-fi-pyrazolone. methyl-.B-pyrezolone.6..." urea from 1-pheny1-(4-phe11yl-4-4:4-diaminostilhene-2:2-disulfonic urea from l-pheny1(4-pheny1-4"-orangislwed.

amino)-3-methyl-5-pyrazolone. acid. amino)-3-methyl-5-pyrazo1one 6..-urea from l-(4-amino-2-methoxy- 4:4-diaminodipheny1-3:3-disultonicureafrom l-(4-aminophenyl)-3- red.

phenyl)-3-methyl-5-pyrazolone. acid. methy1-5-pyrezolone. .1. 7- ureafrom 1-(4-aminophenyl)-3- 4:4-diaminodiphenyl-2:2-disulfonicurea froml-(4-aminopheny1)-3-phen- Do. j

phenyl-5-pyrazolone. acid. y1-5-pyrazolone. w i .l- 8".-- urea froml-(4-aminophenyl)-3- l-(4-aminobenzoylamino)-4-aminourea from l-(4-anino-2-bromopheny])- Do.

methyl-fi-pyrazolone. benzene-3-su1fonic acid. 3-methyl-5-pyrazo1one. j9 do l-(3-aminobenzoylamino)-4aminourea from 1-(4-aminophenyl)-3-meth-Do,

benzene-3-sulfonic acid. yl-fi-pyrazolone.l-(4-aminohenzoylamino)-4-aminoi do -4 L:

benzene-3-carboxy1ic eci l-(3-aminobenzoylamino)-4-aminodobenzene-3-carboxylic acid. 12 do 4:4f-dianinodiphenyi-a:3-dicarboxyl--do i 1 01 l l 13.--- .thiourea from l-(4-aminopheny1)-3- 4:4iamin0-3:3-dihyd.roxydipheny1 thiourea from'1 (ail-aminopheuyl)-3-methyl-5pyrazolone. methyl-5-pyrazolone.-s 14.- urea from l-(4-eminophenyl)-3- -do urea from l-phenyl-(4-phenyl-3:2-methyl-fi-pyrazolone. dimetiiyli -amino) -3-methyl-5- pmwo Monoazodyestufi from l-diazo-G- nitto-2-hydroxynaphthalene--sul- Aromaticdiamine Monoazo dyestufi froml-diazo-G-nitro-2-hydroxynaphthalenei-sulfonic Shade of the dyeing afterNo fonic acid and following dipyrazoacic and following dipyrazoloneaccoppered on lone according to formula I cordmg to formula Iccllulosicfibres 15.-. urea from 1-(4-aminophenyl)-3- 4:4-diaminodipheuyl-sulfone ureafrom1-(4-eminophcnyl)-3-methred ImethyLfi-pyi'azolone'. yl-5-pyrazolone. 16.--- do l 4:4-diammodiphenylsuliox1de do D0,. 4:4-diaminodiphenyl sulfide (in D0.4:4-diaminodiphenylan-lne dn Do. 4:4-diamin0'-2:2{:5:5-tetran1ethoxydo.Do. diphenyl-urea. 4:4-diamino-2:2:5:5-tetraethoxydo Do. vdiphenyl-urea. ,I 21,--- urea from 1-(4-aminopl1eny1)-3-4z4-diamin'odiphenyl methane ureairom1-(4-aminophenyl)-3-ethyl- Do.ethyl-5-pyiazo1oue. 5-pyrazolone. 22 urea from l-(y-amino-3methyll-(3-aminobcnzoylamino)-4-ammourea from l-(4-amino-3-methyl- Do.phenyl)-3-methyl-5-pyrazolone. benzene. phcnyl)-3-methyl-5-pyrazolone.29---- urea from 1-(4-ammopheuyl)-3- 4:4-d1am.1no-3:3'-d1ehlorod1phenylurea from 1-(4-amiuophenyI) -3- Do.

methyl-fi-pyrazolone. i I methyl-s-pyrazolonel .v 24 do414-diamino-3:3-d1n1ethyl-diphenyl -do Do. 25 do4:4-diaminodiphenyl-3:3-dihydroxy- -do Do:

. acetic acid. I 26,"; thiourea from l-(4-'ominophenyl)-3-4:4-diaminodiphenylketone Vthiourea from 1-(4aminophenyl)-3- Domethyl-fi-pymzolone. methyl-5-pyrazolone. 27-thioureafrom1-(4-amino-3-methyl- 4: i-diam1no-3z3-dichlorodiphenylthiourea from l-(4'-amino-3-metl1yl- Do.

phenyl)-3-methyl-5-pyrazolone. methane phenyl)-3-methyl-5'-pyrazolone.28- :'urea from 1-(4'-aminopheny1)-3-4:.4-dian1n1o-3;3-dimethyldiphenylurea from 1-(4-aminophenyl)-3- Do.methyl-5-pyrazolone. methane. methyl-5-pyrazolone. l 29-. do3:3-diamiuo-4:4-d1hydroxydiphenylido Do. urea-b:5-disulfonic acid. 30 do4:4-diamino-3:3-dichlorodiphenyldudes. Do.

sulfone. 31 (in 3:3-diaminn-4:4-dimethoxy-diphendo- Do.

yl-sulfone. i 3:3{-diamino-diphenyl-methauc do Do.ez'idiamino-iifl-dichlorodiphenylldo Do.

e one. I 3 i -urea from l-phenyl-(i phenyl-M-3:3-diamino-4:4-dibromodipheuyldo Do.

aminoHinethyl-S-pyrazolone. ketone. V thiourea from 1-(4-amino-2-chloro-4:4-diamino-stilbenei thiourea from 1-(4-amino2-cl1loro- Do.phenyl)*-3-methyl-5-pyrazolone. phenyl)-3-methyl5-pyrazolone. urea. froml-(QaminophenyD-li- 4: y-diamino-2:2-d1ch'loro-stilbene urea from1-(4-aminophenyl)-3-ethyl-- Do. ethyl-S-pyrazolone. v s-pyrazolone. I37- i 4:442aIninod1pheny1amine-2-sulfonicl do Do aci 38' do1-(4-meth0xy-3-aminohenzoyl-amldo l s Do,

' no)-4-emi.uobenzene. s 39.- urea from l-(4-aminophenyl)-31-(4-amino;benzoylamino)-2z5-dimethurea from 1-(4-aminophenyl)-3-meth-Do.

7 methyl-5-pymzolone, OkY-l-{LIIllIlObQIlZGH yl-s-pyrazolone. 40;...urea from I-(4-a.minophenyl)-3- l-(4-ammobenzoyl-om1no)-2-methurea froml-(4-amiuophenyl)-3- Do.

' methyl-S-pyrazolone. oxy-5-methyl4-aminobenzene. methyl-S-pyrazolone.4I do 4-diaminostilbeue-Z:2-dicarboxylie 0 D 1 8.01 42 (in2:2-diamino-4:4=-dichlorodiphenyldo; l s.. .s 'Do sulfide. 43: fin2;2-diamino-4:4-dichlorodiphcnl-sul -do Do.

foxide.

What I claim 15:. wherein 1n the foregoing formulae Y stands for I. Aprocess for the manufacture of a polyazo dyestufi' which corresponds tothe formula CHs-G 0 and. coupling 2 moles of so obtained monoazodyestufl with 1 mole of a tetrazotised diamine of the formula G O-GH:

a radical selected from. the group consisting. of" methyl, ethyl andphenyl radicals, Z stands for a member selected from the groupconsisting of radicals of the benzene series bound in 1:4-p0sition andof radicals of the diphenyl series bound in 4v:4'-position, R1 and R2each stand for adivalent'radical of the benzene series, and R3, standsfor a, divalent linking member selected from the group consisting of thedirect linkage, -NHCO-NI-I-, NHCO, CI-I:CH, --NI-lI--, -S-, SO2-, -'-CO-and --CH2- radicals.

9 '2. A process for the manufactureof a polyazo dyestuff whichcorresponds to the formula l NO:

which comprises coupling 1 mole of l-diazo-G-nitro-2-hydroxy-naphtha1ene- 4 sulfonic acid with 1 mole of thepyrazolone-urea of the formula dyestuff with 1 mole of the tetrazotiseddfamine of the formula s. A process for the mafiufacture'of'efipoiyaaodye-stuff which corresponds to the formula Newwhich comprises coupling 1mole of 1-diazo-6- nitro-2-hydroxy-naphthalene 4 sulfonic acid 'with 1mole ofthe pyrazolone-urea of the formula om-oo I o'o-oH, 1 1

h .h 4 a m and coupling 21r1o1es ofthe so obtained monoazlodyestufi'with 1 mole of tetrazotised benzidine.

4. A process for the manufacture of a polyazo dyestufi which correspondsto the formula whichicomprises coupling 1 mole of l-diazo-B-nitro-z-hydroxy naphthalene 4 sulfonic acid with'l mole ofthepyrazolone-urea of the formula CHr-CO (JO-CH:

3i1713 11 12 a. nd eoupling 2 moles f the s obtained monoazo ieals, 2stands for a member Selected from he d'yeS f With 1 e 0 the tF ZQ S -Q igroup consisting of radicals of the benzene series of the formula boundin lz-position and of radicals of the di- NHI phenyl series bound in4:4-position, R1 and R:

I k t 0110?) h each stand for a divalent radical of the benzene series;and R3 stands for a divalent linking mem- 5 A polyazo dyestufi whichcorresponds t t her selected from the group consisting of the di- 0 0-0HPN=N 8. The polyazo dyestufl o! the formula no. N=NGH-C o CO-CHN=N iN01 43H: (1B1 no; N=N-OH-CO 0 o-cn-1-r= i 0: 6H; 45H:

PETER HINDERMANN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,845,426 Latten Feb. 16, 19322,155,001 Schmid Apr. 18, 1939 2,191,800 Murphy Feb. 27, 1940 2,195,784Schmid Apr. 2, 1940 2,195,787 Schmid Apr. 2, 1940 2,219,712 Schmid Oct.29, 1940 2,221,360 Schmid Nov. 12, 1940' 2,221,361 Schmid Nov. 12, 19402,221,362 Schmid Nov. 12, 1940 2,228,374 Stusser et a1. Jan. 14, 19412,405,353 Hanhart Aug. 6, 1946 FOREIGN PATENTS Number Country Date248,806 Switzerland Apr. 1, 1948

8. THE POLYAZO DYESTUFF OF THE FORMULA